GB1558530A

GB1558530A - Expanding pulley drive system

Info

Publication number: GB1558530A
Application number: GB3182877A
Authority: GB
Inventors: Gary Alan Woollard
Original assignee: Borg Warner Corp
Current assignee: Borg Warner Corp
Priority date: 1975-06-11
Filing date: 1977-07-28
Publication date: 1980-01-03
Also published as: DE2741146C2; FR2364136A2; DE2741146A1; FR2364136B2

Description

PATENT SPECIFICATION

( 11) 1 558 530 ( 21) ( 61) ( 31) Application No 31828/77 ( 22) Filed 28th July 1977 Patent Addition to No 1550449 dated 21 st May 1976 Convention Application No ( 32) Filed 13th Sept 1976 in 722937 ( 33) United States of America (US) ( 44) Complete Specification Published 3rd January 1980 ( 51) INT CL 3 F 16 H 9/18 55/56 ( 52) Index at Acceptance:

F 2 D 4 A ( 72) Inventor: GARY ALAN WOOLLARD ( 54) EXPANDING PULLEY DRIVE SYSTEM ( 71) We, BORG WARNER CORPORATION, a corporation duly organized and existing under and by virtue of the laws of the State of Delaware, United States of America, having its principal office and place of business at 200 South Michigan Avenue, Chicago, Illinois 60604, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:-

This invention relates to an expanding pulley drive system for transmitting torque from a prime mover, such as an automobile engine, to accessories associated therewith.

More particularly, the invention constitutes an improvement in, or a modification of, the invention as disclosed in our copending application No 21151/76 (Serial No 1 550 449).

In our aforesaid application, we have claimed in claim 1 a drive system for driving accessories and adapted to be disposed between a drive shaft connected, for example, to an engine in a vehicle and a driven shaft connected to one or more accessories, comprising:

a first variable pulley adapted to be rotationally associated with the drive shaft and having an axially fixed flange adapted for connection to the drive shaft and a movable flange movable axially with respect to said fixed flange and the drive shaft; moving means for moving said movable flange axially away from said fixed flange above a predetermined speed of the drive shaft, said moving means comprising a first disc spring adapted to bias said movable flange and centrifugally responsive means associated with said disc spring and actuated by centrifugal force above the predetermined speed of the drive shaft to change the bias of said spring and effect movement of said movable flange; a second variable pulley adapted to be rotationally associated with the driven shaft and the accessories and having an axially fixed flange adapted for connection to the 50 driven shaft and a movable flange movable axially of said fixed flange and said driven shaft; and a second disc spring urging said movable flange of said second pulley axially 55 toward said fixed flange thereof; said variable pulleys being adapted to be drivingly connected with the drive ratio between said pulleys being determined by the position of the movable flanges with 60 respect to their respective fixed flanges; said apparatus being constructed and arranged to provide a fixed drive ratio between the driving and driven shafts at relatively low driving shaft speeds and also 65 to provide a substantially constant speed of the driven shaft for speeds of the driving shaft above said predetermined speed thereof throughout the major portion of the normal vehicle operating range 70 According to the present invention there is provided a drive system as claimed in claim 1 of application No 21151/76 (Serial No.1 550 449), wherein each of the first and second disc springs which couples the 75 axially movable pulley flanges to the driving and the driven shafts respectively has at least one flat chordal surface on its periphery which cooperates with a complementary flat chordal surface on a part to 80 provide the required driving and driven connection between the axially movable pulley flanges and the respective drive and driven shafts.

In order that the invention may be well 85 understood there will now be described one embodiment thereof, given by way of example, reference being had to the accompanying drawings in which:

Figure 1 is a sectional view (parts of 90 00 ID ( 1 1 558 530 which are omitted for clarity) through a drive system generally as disclosed in our copending application No 21151/76 (Serial No.1 550 449), the system being shown at idle position; Figure 2 is a plan view of a disc spring usable in the system of Figure 1, and Figure 3 is a partial view of the rim of a spring retainer usable with the disc spring of Figure 2.

In Figure 1 there is illustrated a drive system comprising a drive shaft 10 adapted to be connected to the crankshaft 11 through the usual vibration damper 12, of for example, an automobile engine (not shown) Associated with the crankshaft is a variable driver pulley, generally identified at 13, which comprises an axially fixed flange 14 and an axially movable flange 16 for which an actuator mechanism is provided which includes a cup-shaped drive member 42, the rim 44 of which engages the outer peripheral rim 45 a of a disc spring 46.

In the present embodiment, the drive system as disclosed in our aforementioned application is modified in that the rim 45 a is formed with one or more flats 45 b which cooperate with flats 44 a of the drive member 42 to provide a positive driving coupling between the disc spring 46 and the drive member 42, the flats 45 b being chords of the circle defined by the disc spring.

Torque transmission between the fixed pulley flange 14 and the movable pulley flange 16 occurs due to the positive drive coupling of the flats 45 b and 44 a at the outer rim of the disc spring 46 and the corresponding rim 44 of the retainer 42, respectively.

The driven shaft 70 comprises a variable driven pulley 82 which comprises a fixed flange 84 and a movable flange 86.

Abutting the forwardly extending rim 96 of flange 86 of the pulley 82 is a disc spring 104 which is of a construction similar to the 45 disc spring 46 associated with the driving shaft 10 previously described herein Thus, the disc spring 104, like the previously described disc spring 46, is modified as compared with the like component in our 50 aforementioned application, by being formed with flattened surfaces which are actually chords of the disc spring and provide positive connections as described with reference to the disc springs 46 55 Because of the similarity, the disc spring 104 is not separately illustrated with the flat chordal surfaces, as is the disc spring 46.

Claims

WHAT WE CLAIM IS:- 1 Drive system as claimed in claim 1 of 60 application No 21151/76 (Serial No.

1 550 449), wherein each of the first and second disc springs which couples the axially movable pulley flanges to the driving and the driven shafts respectively has at 65 least one flat chordal suface on its periphery which cooperates with a complementary flat chordal surface in a part to provide the required driving and driven connection between the axially movable pulley flanges 70 and the respective drive and driven shafts.

2 Drive system as claimed in claim 1 and substantially as herein described with reference to the accompanying drawings.

A A THORNTON & CO, Northumberland House, 303 306 High Holborn, London, W C 1.

Printed for Her Majesty's Stationery Office by MULTIPLEX techniques ltd, St Mary Cray, Kent 1979 Published at the Patent Office, 25 Southampton Buildings, London WC 2 l AY, from which copies may be obtained.